Updates to CoreValve Extreme Risk Study Encouraging

Two-year data and numerous substudies are showing how high-risk and extreme-risk patients with aortic stenosis, even those with frailty, disability or comorbidities, can benefit from transcatheter aortic valve replacement (TAVR), experts said at a TCT 2015 didactic symposium.  

Performance goals met

In the CoreValve US Pivotal Extreme Risk Study, 2-year follow up in 305 patients (mean age, 83.2 years) who received TAVR with the self-expanding CoreValve device (Medtronic), showed a rate of all-cause mortality or stroke of 38% (95% CI 33.6-42.3%). This was well below the performance goal of 57.9%, said Michael J. Reardon, MD, FACC, FACS, of Weill Medical College at Cornell University in New York, and Houston Methodist Hospital in Houston, Texas.

In the CoreValve US Pivotal High Risk Study, 2-year follow up in 499 patients (mean age, 83.1 years) found a lower rate of all-cause mortality rate for the TAVR group than for the SAVR group (22.2% vs. 28.6%; P = .04). Additionally, TAVR patients had lower rates of all stroke (10.9% vs. 16.6%; P = .05) and major stroke (6.8% vs. 9.8%; P = .025), he said.

High-risk patients undergoing TAVR had higher rates of major vascular complications and pacemaker implants, but lower rates of major bleeding, new or worsening AF and acute kidney injury compared with those undergoing SAVR, he added.

TAVR also resulted in particularly favorable 2-year mortality rates for patients with STS-predicted mortality ≤ 7% (15% vs. 26.3% for SAVR; P = .01).

Encouragingly, Reardon noted, the United States commercial experience with CoreValve “seems to be tracking … what we saw in the [Investigational Device Exemption] trial, with very low mortality.”

Risk score developed

Also highlighting data from the CoreValve Extreme Risk Study, Jeffrey J. Popma, MD, of Harvard Medical School and Beth Israel Deaconess Medical Center, in Newton, Mass., said the trial has enabled determination of independent predictors for 30-day mortality.

These include use of home oxygen (HR 1.74; 95% CI 1.16-2.61), assisted living (HR 1.68; 95% CI 1.05-2.69) and albumin < 3.3 g/dL (HR 1.6; 95% CI 1.04-2.47), with a trend seen for age greater than 85 years (HR 1.46; 95% CI 0.99-2.15).

The study investigators combined those four factors into a risk score, and stratified patients into quartiles based on it, Popma said. For those in the lowest quartile, 30-day mortality was 3.6%, compared with 6.6% for those in the middle two quartiles and 10.9% for those in the highest quartile (Log-rank P = .002 ).

Multivariable predictors of 1-year mortality were home oxygen (HR 1.9; 95% CI 1.47-2.44), albumin < 3.3 g/dL (HR 1.4; 95% CI 1.04-1.91), falls in the past 6 months (HR 1.36; 95% CI 1.03-1.81) and STS-PROM > 7% (HR 1.36; 95% CI 1.05-1.77) with a trend for severe Charlson comorbidity index (HR 1.27; 95% CI 0.98-1.65).

Additionally, 1-year mortality risk levels rose with increasing 1-year risk level scores (P < .001).

“We went in prospectively and said, `let’s learn about frailty, let’s learn about disability and let’s learn about comorbidities,’” Popma said. “Those are probably important factors to determine long-term prognosis of patients. We are coming up with [a way] to determine which patients are going to be affected by early and late mortality.”

Disclosures:

• Popma reports relationships with multiple device companies. 
• Reardon reports receiving consulting fees/honoraria from Medtronic.